1. Field of the Invention
The present invention relates to a resistor paste composition and a ceramic substrate. More particularly, it relates to a resistor paste comprising SiO.sub.2 -B.sub.2 O.sub.3 system glass containing metal oxides, and SnO.sub.2 and/or Sb-doped SnO.sub.2, which is useful for a ceramic substrate, whereby even when fired in a non-oxidizing atmosphere, it will not be reduced, and provides adequate stability of e.g. resistivity.
2. Discussion of Background
Heretofore, the resistor in a hybrid integrated circuit has been formed in such a manner that a silver (Ag) or Ag-palladium (Pd) conductor is formed on or in a ceramic substrate, and a resistor paste is printed between the conductor patterns, followed by firing in an oxidizing atmosphere such as air at a temperature of from about 850.degree. to 900.degree. C. The resistor paste used in such a case used to be composed mainly of RuO.sub.2 and glass. However, recently, it has been common to employ a copper (Cu) conductor instead of the Ag or Ag-Pd conductor, from the viewpoint of the reliability in e.g. migration.
However, the Cu conductor is oxidized unless it is fired in a non-oxidizing atmosphere such as nitrogen. In a non-oxidizing atmosphere, RuO.sub.2 can not be used, since it will be reduced and will not form a resistor in such a non-oxidizing atmosphere.
Therefore, it has recently been proposed to employ a combination of antimony (Sb)-doped tin oxide and glass powder (Japanese Unexamined Patent Publication No. 119902/1987). However, such a combination still has a drawback that the resistivity and the temperature coefficient of resistivity (TCR) are not yet adequately stable.